From: Kenneth Graunke Date: Thu, 22 Jan 2015 07:25:56 +0000 (-0800) Subject: nir: Add algebraic optimizations for pointless shifts. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=551a752a592703a97dcee74765463bb15ccb8b14;p=mesa.git nir: Add algebraic optimizations for pointless shifts. The GLSL IR optimization pass contained these; we may as well include them too. v2: Fix a >> 0 and a << 0 optimizations (caught by Matt). No change in the number of NIR instructions on a shader-db run. total i965 instructions in shared programs: 6035397 -> 6035392 (-0.00%) i965 instructions in affected programs: 542 -> 537 (-0.92%) helped: 2 (in glamor) Signed-off-by: Kenneth Graunke Reviewed-by: Jason Ekstrand Reviewed-by: Matt Turner --- diff --git a/src/glsl/nir/nir_opt_algebraic.py b/src/glsl/nir/nir_opt_algebraic.py index 53fe4a0804e..be9487031d2 100644 --- a/src/glsl/nir/nir_opt_algebraic.py +++ b/src/glsl/nir/nir_opt_algebraic.py @@ -80,6 +80,13 @@ optimizations = [ # DeMorgan's Laws (('iand', ('inot', a), ('inot', b)), ('inot', ('ior', a, b))), (('ior', ('inot', a), ('inot', b)), ('inot', ('iand', a, b))), + # Shift optimizations + (('ishl', 0, a), 0), + (('ishl', a, 0), a), + (('ishr', 0, a), 0), + (('ishr', a, 0), a), + (('ushr', 0, a), 0), + (('ushr', a, 0), 0), # This one may not be exact (('feq', ('fadd', a, b), 0.0), ('feq', a, ('fneg', b))),